Two of the most common, conventional types of integrated circuit packages are gull-wing leaded packages and ball grid array or "flip chip" packages. Each type of package has a corresponding configuration of pads on a circuit board designed to accommodate the package and to provide reliable electrical contact and physical adhesion of the package to the circuit board.
Generally, a gull-wing leaded package, and in particular a ceramic package, is more costly to assemble than a ball grid array package because each lead must be individually brazed onto the package. Substitution of ceramic gull-wing leaded packages with ball grid array packages is therefore generally more economical. However, when a circuit board is already in production, substitution of ceramic gull-wing leaded packages with ball grid array packages may not be cost effective, because a substantial redesign of the circuit board would be necessary to accommodate a conventional ball grid array package.